Sex scandals in entertainment and politics seem to be exploding, as increasing numbers of women, and sometimes men, say they have been sexually assaulted or harassed by the powerful.

But in politics, sex scandals are nothing new, and allegations of misconduct have swirled around a number of U.S. presidents, including the current White House occupant, Donald Trump.

At least a half-dozen presidents may have had sexual affairs, beginning with the third president, Thomas Jefferson.

Many historians believe that Jefferson fathered children by one of his slaves, Sally Hemmings, a liaison rumored in his lifetime and supported by modern DNA tests that show a link between the Jefferson and Hemmings family lines.

In the 20th century, President Lyndon Johnson was an accomplished legislator and chief executive, but biographers say he was also a womanizer and had numerous sexual affairs inside and outside the White House.

President John Kennedy had relations with many women, his biographers say, famously including the glamorous Hollywood actress Marilyn Monroe.

‘Seduction’

One presidential historian says it’s not surprising that some politicians have strayed from their marriage vows.

“What is politics if it’s not seduction?” asked Richard Reeves, who has written books on five presidents. “That’s what they do for a living.”

FILE - President John F. Kennedy and first lady Jacqueline Bouvier Kennedy arrive at Love Field in Dallas, Texas, Nov. 22, 1963.

Kennedy’s close relationship with the press kept his liaisons from the public during his lifetime, something that would be unlikely in the internet age, said Reeves, who teaches at the Annenberg School for Communication and Journalism at the University of Southern California.

Consenting relationships between adults are not illegal, notes legal scholar Ariela Gross, who teaches at USC’s law school.

“We also want to be able to distinguish between people who are predators going after 14-year-old girls, and incidents that, while bad, wouldn’t be criminal or perhaps even actionable sexual harassment if they were in a court of law,” Gross said.

Former Alabama Chief Justice and U.S. Senate candidate Roy Moore speaks at a news conference with his wife, Kayla, in Birmingham, Ala., Nov. 16, 2017.

She was referring to allegations against U.S. Senate candidate Roy Moore of Alabama, who is accused of groping teenaged girls decades ago when he was a prosecutor nearly 20 years their senior.

Moore has lost much of his support among fellow Republicans, including that of the Republican National Committee. While Trump has voiced support for Moore, he has not given the candidate a full endorsement.

Beleaguered Minnesota Senator Al Franken, a Democrat, could face a Senate ethics investigation over allegations that he kissed a woman against her will and groped her while she was asleep when the two were on tour as entertainers to military posts in 2003. A photograph from the time shows the groping.

It happened before Franken had embarked on his political career, but he was recently accused of grabbing women’s buttocks while making an official appearance as a U.S. senator.

FILE - Then first lady Hillary Clinton watches her husband, President Bill Clinton, pause as he thanks those Democratic members of the House of Representatives who voted against his impeachment, Dec. 19, 1998.

​Shook the political system

Allegations of sexual assault surrounding former President Bill Clinton shook the political system in 1998.

Clinton was accused of lying under oath and obstructing justice when questioned about a sexual relationship with White House intern Monica Lewinsky. He survived the impeachment vote in the Senate.

“There’s no question that Clinton got lucky,” presidential biographer Reeves said. “Again, if the web were around, he probably wouldn’t have survived.”

Reeves notes that the internet has changed the pace and tenor of political news coverage.

About 16 women have accused Trump of sexual harassment or worse. He has labeled the accusations “fake news” in both online tweets and other statements.

None of the allegations has been proved, but in a tape from 2005, the future president was heard boasting about groping women. The tape was released before last year’s election.

“That case is remarkable in that if he did the things that he bragged about on tape, grabbing women, as he said, by their private parts, that would be sexual assault,” legal scholar Gross said, noting that sexual assault is a criminal act. “Of course, our evidence is simply what he has said.”

Men, including presidents, have been known to exaggerate, historian Reeves says. Moreover, women and men may disagree on what happened between them, and rivals and opponents can publicize assertions, whether true or not.

The scholars say victims of sexual assault have become emboldened, and while the truth of allegations can be difficult to determine, a critical public is holding those in power, including presidents, accountable for behavior behind closed doors.